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Arakawa M.,Tohoku University | Kushibiki J.-I.,Tohoku University | Ohashi Y.,Tohoku University | Maruyama Y.,Tohoku University | And 10 more authors.
Japanese Journal of Applied Physics | Year: 2015

We developed a procedure for fabricating a Fabry-Perot optical cavity with less long-term length variation. We fabricated a homogenized TiO2- SiO2 ultralow-expansion (ULE) glass ingot from a commercial TiO2-SiO2 ULE glass ingot with striae. We also controlled the zero-crossing temperature of the coefficient of thermal expansion of the homogenized ingot to approximately 30 °C by heat treatment at 970 °C for 72 h to change the fictive temperature of the ingot. A 100-mm-long cavity spacer was carefully fabricated while reducing the mechanical residual stress introduced by machining. A cavity composed of the spacer and two mirrors of 39-layered Ta2O5/SiO2 films exhibited a high finesse of 420,000 at 729nm and a high length stability of 13 fm/day after 500 days from the beginning of the measurement at a constant temperature of 29.78 °C. © 2015 The Japan Society of Applied Physics.

Torikai T.,Japan Aviation Electronics Industry | Yamauchi T.,Japan Aviation Electronics Industry | Aihara S.,Japan Aviation Electronics Industry | Mine S.,Mitsubishi Group | And 6 more authors.
POF 2012: 21st International Conference on Plastic Optical Fibers - Proceedings | Year: 2012

We have developed an optical I/O connector embedded using optical collimator lenses fabricated with well-defined and proven ball-point pen technology. The collimator lens consists of a glass-ball lens and a plastic optical fiber (POF) in a ball-point pen type metal sleeve. The POF is point-crimped in the sleeve without any adhesives. This enables a reliable fiber assembly without any damage to the POF, because the sensitive fiber end-facet is protected by the surrounding glass-ball and metal sleeve. The coupling loss is as low as 3dB, including Fresnel losses between engaged plug and receptacle collimator lenses. This optical I/O connection scheme has encouraged us to promote the POF as a cost-effective interconnection medium into the consumer electronics market. © 2012 ICPOF.

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